Half-Life: Further Data is a series of companion CDs, distributed for free via retail channels in 1999. Two CD releases are known: Half-Life: Further Data V.1, a CD-ROM / audio CD hybrid disc; and Half-Life: Further Data V.2, a CD-ROM data only disc.

Further Data V.1 contains the Half-Life 1.0.0.5 to 1.0.0.8 game update, while Further Data V.2 contains the 1.0.0.5 to 1.0.0.9 game update, allowing for installation of Team Fortress Classic. Further Data V.1 is a hybrid data/audio CD, featuring two tracks from the Half-Life soundtrack ("Adrenaline Horror" and "Space Ocean"). Both releases contain the Half-Life: Uplink demo, and Half-Life: Further Data, a collection of multiplayer maps, models and logo sprays.

Further Data is a reference to the sentence shown at the very end of Uplink, "further data required".

Exact release dates for the CDs are not currently known. All files on the
Further Data V.1 CD have a creation date of February 17, 1999. By comparison, Half-Life: Uplink was released on February 12, 1999). Creation dates on the
Further Data V.2 CD vary, with the latest date being June 10, 1999.